NAME_______________
DATE
Composition of the Cell Membrane and Functions
The cell membrane is also called the ____________ membrane and is
made of a phospholipid____________ .The phospholipids have a
hydrophilic (water attracting) ____________and two hydrophobic
(water repelling) ____________ . The head of a phospholipid is made of
an alcohol and a ____________group, while the tails are chains of
____________. Phospholipids can move ___________ and allow water
and other ___________ molecules to pass through into or out of the cell.
This is known as simple ____________ because it does not require
_____________ and the water or molecules are moving____________
the concentration gradient.
Another type of lipid in the cell membrane is
_CHOLESTERAL that makes
nym?rane more fluid.
Embedded in the phospholipid bilayer
OTEINS_ that also aid in
diffusion and in cell recognition. Proteins called _INTEGRAL_
proteins go all the way thFöüUh¯fhe bilayer, while
_PERIPHERAL_ proteins are only on one side. Integral proteins are
also called _CHANNEL_ proteins. Large molecules like _LIPIDS_
or carbohydrates use proteins to help move across cell membranes.
Some of the membrane proteins have carbohydrate _RECEPTORS_
attached to help cells in recognize each other and certain molecules.
List 4 functions of the cell or plasma membrane:
a.
b.
c.
Cell membranes help organisms maintain homeostasis by
controlling what substances may enter or leave cells
_exchange materials such as food, water, & wastes with its
environment
_water, oxygen, & carbon dioxide can move in and out freely
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d.
is semi-permeable or selectively permeable only allowing
certain molecules to pass through
Correctly color code and identify the name for each part of the cell
membrane.
Letter
Name/Color
Phospholipid bilayer
Letter
Name/Color
Peripheral protein
(red)
Integral protein (pink)
Fatty acid tails
(orange)
Phosphate heads
(yellow)
Cholesterol (blue)
Glycoprotein (green)
Glycolipids (purple)
C
E
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Match the cell membrane structure or its function with the correct
letter from the cell membrane diagram.
Letter Structure/Function Letter Structure/Function
Attracts water
Helps
maintain
flexibility
of
membrane
Repels water
Make up the bilayer
Involved in cell-to-cell
Help transport certain
materials across the cell
recognition
membrane
Osmosis and Tonicity
Define osmosis. _MOVEMENT OF WATER DOWN
CONCENTRATION
GRADIENT_
In which direction does water move across membranes, up or down
the concentration gradient? _________________
Define these 3 terms:
a. isotonic
b. Hypertonic
c. hypotonic
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Use arrows to show the direction of water movement into or out of
each cell.
WATER
WATER 100%
Match the description or picture with the osmotic condition:
Isotonic
C solution with a lower solute concentration
A solution in which the solute concentration is the same
A condition plant cells require
A condition that animal cells require
When a red blood cell bursts (cytolysis).
When a plant cell loses turgor pressure (Plasmolysis)
A solution with a higher solute concentration
A plant cell with good turgor pressure
A solution with a high water concentration
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Label the tonicity for each solution (isotonic, hypotonic, or
hypertonic):
H20
H20
HYPO
rso
HYPER
H20
H20
HYPO Hypo Hypn Transport Requiring Energy
What type of transport is represented by the following picture?
ACTIVE
What energy is being used? ATP
In which direction (concentration gradient), is the movement occurring?
AGAINST(UP)
Color the internal environment of the cell yellow. Color and Label
the transport proteins red and the substance being moved blue.
OUTSIDE CELL
One type of active transport is called the _Na/K pump which helps
muscle cells contract. This pump uses _ENERGY to move ions
UP the concentration gradient. The protein that is used to pump the
ions through is called a CARRIER protein and it changes its
SHAPE to move the ions across the cell membrane. Label and
color the carrier proteins red and the ions green.
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